Enhancement and standardization of benthic macroinvertebrate monitoring and analysis tools for the Puget Sound region

With funding from an EPA grant from 2010-2014, King County worked with regional partners and experts to enhance data analysis tools and encourage collaboration and standardization for benthic macroinvertebrate monitoring in the Puget Sound region.

B-IBI Results Table screenshot from http://pugetsoundstreambenthos.org/
B-IBI Results Table screenshot from http://pugetsoundstreambenthos.org/

This project built on and updated the widely used multi-metric Puget Lowland benthic index of biotic integrity (B-IBI) initially developed in the early 1990’s to report stream health. Field collection methods were compared, taxa attributes were updated based on scientific literature or were empirically derived, and the B-IBI was recalibrated based on a spatially extensive data set representative of the Puget Sound region using a refined scoring techniques. The new taxa attributes and recalibrated B-IBI were incorporated into the Puget Sound Stream Benthos (PSSB) data management system. In addition, the entities using the PSSB and the breadth of data in the PSSB increased.

Key Project Accomplishments

  • Updated taxa attribute lists (long-lived, predator, clinger) with new scientific information; updated intolerant and tolerant taxa attributes with empirically-derived data from over 700 sites in the Puget Sound region.
  • Adjusted B‑IBI metric scores so that the final B‑IBI is based on continuous scoring without gaps, has strong signal to noise discrimination, and is independent of taxonomic effort.
  • Confirmed comparability of regional macroinvertebrate data collected from different sampling surface area protocols used by various entities in the Puget Sound region.
  • Verified that natural site features do not add a consistent source of bias for B‑IBI.
  • Evaluated the biological risks of common aquatic stressors, which revealed stressors related to substrate and water quality were the most influential to B‑IBI scores.
  • Enhanced the analytical capabilities and functionality of the PSSB database management system by incorporating updated attributes, taxonomic levels, and B‑IBI scoring; new and historical B‑IBI data added to the PSSB.
  • Increased multi-agency participation and partnership within the Puget Sound region as demonstrated by attendance and participation in field and PSSB trainings and regional workshops.

Primary Project Outcomes

This project supported collaboration and assessment at the regional level by:

  • Hosting regional workshops to share how agencies and jurisdictions are using biological data;
  • Providing training for field collection and data management via the PSSB;
  • Connecting people and programs at the local, state, tribal and federal levels; and
  • Improving B-IBI to support status and trends and NPDES stormwater permit monitoring as recommended by the Puget Sound Stormwater Workgroup to the Washington Department of Ecology.

Final Technical Documents

Updating the Benthic Index of Biotic Integrity (B-IBI): Outcomes and Key Findings
Elene Dorfmeier, Leska Fore, Jo Wilhelm, and Deb Lester

This report provides an overview of the key outcomes accomplished by this grant, an overview of the regional impact this project has made, and examines how this effort has promoted the use of B-IBI throughout the Puget Sound region.

Recalibration of the Puget Lowland Benthic Index of Biotic Integrity (B-IBI)
Jo Wilhelm, Leska Fore, Deb Lester, and Elene Dorfmeier

Metric scoring was modified to a continuous scale, rescaling the original 1, 3, 5 discrete scoring system, so that each of the 10 metrics was scored 0-10. Total B-IBI range was expanded from 10-50 to 0-100. Scoring for three metrics was adjusted to account for taxonomic effort. Standardizing metric scaling to a continuous, rather than discrete scale, decreased variation of the recalibrated index 41% compared to the original scoring system.
About the Author: 
Elene Dorfmeier, Deb Lester, and Jo Opdyke Wilhelm are from the King County Water and Land Resources Division of the Department of Natural Resources and Parks. Leska Fore is with the Puget Sound Partnership.